The present invention relates to a method for the provision of dielectric isolation in an epitaxial layer and for the isolation and protection of pn-junction of a compound semiconductor of an integrated circuit by selectively oxidizing the compound semiconductor by means of an oxidizing gas plasma.
The conventional method for the provision of such isolation and protection for the compound semiconductor element is to first provide a groove by mesa-type etching and thereafter chemically deposit silicon oxide (SiO.sub.2) film thereon to passivate the surface. Such a conventional method involves considerable drawbacks in that the treatment, because of its complexity, sometimes decreases the reliability, the degree of integration and the yield. Furthermore compatibility with the other processes must be taken into account when the process is made in a chain of continuous processes.